Fig. 2

The fourth-passage spheres enhanced carcinogenicity in vitro and in vivo. The fourth-passage spheres showed higher sphere formation rate than primary-passage spheres (a), the fourth-passage spheres showed higher colony formation rate than primary-passage spheres (b), the fourth-passage spheres exhibited higher migration and invasion rates (c), the IC₅₀ of primary-passage spheres and the fourth-passage spheres (d), the relative density of primary-passage spheres and the fourth-passage spheresof ABCG2 and Oct4 (e), Data were presented as mean ± SD (n = 3,^*P < 0.05). The tumorigenicity of the fourth-passage spheres and parental SK-UT-1 cells in vivo (f–g). The BLAB/C-nu female mice injected with10⁵, 10⁶ parental cells SK-UT-I could not form tumors. Data were presented as mean ± SD (n = 5,^*P < 0.05)